Treatment of a substance is understood as the application and shaping or sculpturing of the substance on a surface, as opposed to scraping and removal of the substance from the surface. The surface pertains to an object or body, but reference to the surface of an object is also meant to be a reference to the surface of a body.
It is well known that very often, when a knife, even a butter knife, is used to spread butter on a cracker, or other brittle food, the cracker breaks before the butter is spread. The reason is that forces applied to the butter are also transferred from the knife, via the butter or directly, to the cracker. Likewise, when a spatula is used to dress a large open wound by application of a layer of unguent, the pressure exerted by the spatula is a problem since it not only spreads the ointment but also presses on the open wound, which is painful to the patient.
Therefore, it is desirable to use tools that allow the application of controlled force to a treated substance, and to the surface onto which the substance is treated, and prevent the transmission of excessive forces, to avoid causing damage to the surface of and to the object or body. Known putty knives and spatulas do not provide the desired solution.
Improvements to spatulas may deal with the human engineering aspects of the tool. In U.S. Pat. No. 5,956,799, Cummings et al. disclose improvements to make the handle ergonomically superior, comfortable for use, and convenient and easy to insert and retrieve from a pocket. The handle has an inner core and a softer overlay.
In US Patent No. US 2003/0200619, to Kelsey et al., reference is made to “a spatula for personal use” but the term spatula is not used in the conventional meaning since there is divulged a spatula “used in the manner of a scraper or a strigil”. There is described a hand-tool for the removal of a preparation applied to the skin, with a material-removal blade made of an elastomeric material, at one or both ends of a handle.